/* This program will ping a VRPN server and time how long it takes the server
   that is being pinged to respond.  It makes use of the VRPN ping/pong
   mechanism by which objects detect if they have connected to servers.
   It gives an indication of the round-trip time from a message at the user
   level from a client through the user level at a server.
*/

#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <signal.h>
#include <vrpn_Connection.h>
#include <vrpn_Text.h>

vrpn_Text_Receiver * r;
vrpn_Connection * c;
vrpn_int32	ping_message_id;
vrpn_int32	pong_message_id;
vrpn_int32	sender;

struct timeval	now;
struct timeval	last_ping;

void handle_cntl_c (int)
{
  exit(0);
}

int	my_pong_handler(void *userdata, vrpn_HANDLERPARAM p)
{
	static	int	count = 0;
	static	double	min = 10000, max = 0, sum = 0;

	// See how long it has been between the ping request and
	// the pong response.
	struct timeval	diff;
	vrpn_gettimeofday(&now, NULL);
	double msecs;
	diff = vrpn_TimevalDiff(now, last_ping);
	msecs = vrpn_TimevalMsecs(vrpn_TimevalNormalize(diff));

	// Keep statistics on the length (min, max, average)
	if (msecs < min) { min = msecs; };
	if (msecs > max) { max = msecs; };
	sum += msecs;

	// Print and reset the statistics every once in a while
	if (++count == 500) {
		printf("Min = %4.2g, Max = %4.2g, Mean = %4.2g\n",
			min, max, sum/count);
		count = 0;
		min = 10000;
		max = sum = 0.0;
	}

	// Send a new ping request, and record when we sent it.
	// REMEMBER not to call mainloop() within the handler.
	vrpn_gettimeofday(&last_ping, NULL);
	c->pack_message(0, last_ping, ping_message_id, sender, NULL,
		vrpn_CONNECTION_RELIABLE);
	c->send_pending_reports();

	return 0;
}

int main(int argc, char* argv[])
{
	// Declare a new text receiver (all objects are text senders)
	// and find out what connection it is using.
	r = new vrpn_Text_Receiver (argv[1]);
	c = r->connectionPtr();

	// Declare the same sender and message types that the BaseClass
	// will use for doing the ping/pong, so we can use the same
	// mechanism.  Register a handler for the pong message, so we
	// can deal with them.
	ping_message_id = c->register_message_type("Server, are you there?");
	pong_message_id = c->register_message_type("Server is here!");
	sender = c->register_sender(vrpn_copy_service_name(argv[1]));
	c->register_handler(pong_message_id, my_pong_handler, NULL, sender);

	// Let the user kill the program "nicely."
	signal(SIGINT, handle_cntl_c);

	// Wait a few seconds (spinning while we do) in order to allow the
	// real pong message to clear from the system.
	struct timeval	then, diff;
	vrpn_gettimeofday(&then, NULL);
	do {
		vrpn_gettimeofday(&now, NULL);
		r->mainloop();
		diff = vrpn_TimevalDiff(now, then);
	} while ( vrpn_TimevalMsecs(vrpn_TimevalNormalize(diff)) < 2000);

	// Send a new ping request to the server, and start counting how
	// long it takes to respond.
	vrpn_gettimeofday(&last_ping, NULL);
	c->pack_message(0, last_ping, ping_message_id, sender, NULL,
		vrpn_CONNECTION_RELIABLE);

	// Loop forever.
	while (1) {
		r->mainloop();
	}
}

